1. Field of the Invention
The present invention relates to convertible bulk hand trucks that are adjustably positioned between folded and unfolded positions to define either a two wheeled dolly or a four wheeled platform and more particularly to such convertible bulk hand trucks having lift off top components in combination therewith.
2. Description of the Prior Art
Convertible bulk hand trucks having a main frame and a foldable subframe that are folded together for forming a two wheeled dolly device and that are positioned in an unfolded position to form a four wheeled cart are shown in U.S. Pat. Nos. 3,785,669 and 4,921,270. While suitable for their intended purpose, a problem with such trucks is that, in the four wheel cart position, the goods that are transported on the four wheel cart are located at floor level requiring bending and lifting movements as the goods are shifted from the cart in warehouses, shops, stores or from loading docks onto common carriers. While the load carrying capacity is dependent upon the number of articles such as crates, cartons, barrels or the like that can be positioned on the four wheel cart sometimes it is preferable to load and unload the goods from a more elevated position. Furthermore, in such applications it can be desirable to have a work and support surface located at table top level to carry out trimming or other operations as well as to facilitate loading and unloading of goods and products.
Other wheeled devices and table combinations are shown in U.S. Pat. Nos. 4,284,286; 4,565,382; 5,004,263; 5,160,182 and 5,201,536, none of which have the configuration or functional capability of serving as a two wheeled dolly and a four wheeled cart while also including features that serve to convert the four wheeled cart into a portable work table.